A resource block group (RBG) is a group of continuous centralized virtual resource blocks (VRB). An RBG size indicates a quantity of VRBs included in each RBG. A virtual resource block may be a physical resource block (PRB), or may be an RB obtained after a PRB is converted according to a specific rule, or may be an RB in a general sense. In Long Term Evolution (LTE), an RBG size is usually a fixed size determined based on system bandwidth. For example, when the system bandwidth is less than or equal to 10 RBs, the RBG size is one RB, that is, one RB is one RBG; or when the system bandwidth includes 11 RBs to 26 RBs, the RBG size is two RBs, that is, two RBs are one RBG.
With evolution of a communications system, a 5th Generation (5G) new radio (NR) communications system is under research. In 5G NR, system bandwidth may be 100 M, 400 M, 500 M, or the like, and the system bandwidth may be divided into one or more bandwidth parts (BWP or BP). To support different services, different frame structure parameters (such as a subcarrier spacing and/or a CP length) may be used for different BPs, and a slot or a mini-slot is used as a scheduling unit. However, different frame structures result in that BPs of a same size include different quantities of RBs. In addition, time domain scheduling resources in NR may be flexibly scheduled. Therefore, a requirement of 5G NR cannot be met by determining an RBG of a fixed size based on system bandwidth in LTE.